Influence of homopolysaccharide‐producing lactic acid bacteria on the spreadability of raw fermented sausages (onion mettwurst)

Abstract

The purpose of the study was to investigate the effect of a reduced pH value (5.1 instead of 5.5 to 5.6) on the properties of highly perishable, spreadable raw fermented sausages (onion mettwurst) with or without the addition of homopolysaccharide (HoPS)-producing lactic acid bacteria (LAB). Hence, sausages with HoPS-producing LAB and a pH value of 5.1 were produced and compared to sausages (pH 5.1) produced with a non-exopolysaccharide (EPS)-forming strain (Lactobacillus sakei TMW 1.2037). Microbial growth and pH values were monitored during processing (24°C for 48 hr, 10°C for 24 hr) and storage (14 days at 0 to 2°C). Furthermore, fat (Weibull-Stoldt) and EPS contents were determined in the final products. Sausages were characterized using texture profile and sensory analysis. The fat contents ranged from 16% to 19% and the determined EPS concentrations ranged from 0.17 to 0.59 g/kg for L. sakei TMW 1.411 and Lactobacillus curvatus TMW 1.1928 and from 0.67 to 1.58 g/kg for L. curvatus TMW 1.51. The strains L. sakei TMW 1.411 and L. curvatus TMW 1.51 reduced the hardness of the samples significantly (P < 0.05) compared to the control samples. Regarding spreadability and mouthfeel, sausages containing an EPS-forming culture were rated slightly better than the control samples and the taste was not negatively influenced.Practical Application: This study clearly demonstrated that it is promising to apply HoPS-producing LAB to maintain the spreadability of pH-reduced (pH 5.1) spreadable raw fermented onion mettwurst, which may prospectively give the opportunity to increase the safety of this highly perishable product.

Usage of in situ exopolysaccharide‐forming lactic acid bacteria in food production: Meat products—A new field of application?

“…The negative effect observed in the study of Velasco, Weiss, and Loeffler (2020) could however be promising for spreadable, fat‐reduced meat products where a softening effect would improve the product quality and may facilitate the production of semidried sausages with lower pH values, which could contribute to the shelf life of such products. This softening effect of EPS was also confirmed by Hilbig, Hildebrandt, Herrmann, Weiss, and Loeffler (2020), who were able to produce spreadable raw fermented onion mettwurst with a lowered pH value using the EPS‐producing strain L. sakei TMW 1.411. Usually, a decrease in pH close to the isoelectric point of meat proteins (∼5.0) leads to a reduced net charge of the proteins, which affects electrostatic repulsion and hence the stability as well as the spreadability of the sausages.…”

“…Hilbig et al (2019) found a contrary relationship when using EPS-forming starter cultures in fat-reduced teewurst, in order to cover fat-free parts on protein particles thereby maintaining spreadability (Figure 1). Also in their other studies performed in meat products, HoPSforming strains were found to be more promising (Hilbig et al, 2019a(Hilbig et al, , 2019b(Hilbig et al, , 2020. However, Vincent, Faber, Neeser, Stingele, and Kamerling (2001) indicated in their study that side chains of EPS are of key importance with respect to their texturizing properties although these side chains were shown to convert polysaccharides into more compact structures possessing a lower viscosifying capacity (Cui, 2005).…”

“…When it comes to meat matrices, processing conditions and meat matrix composition should be considered with respect to EPS formation and function as illustrated in Figure 1. Since L. sakei TMW 1.411 was found to be a promising strain with regard to structural and textural changes in meat products, it may be a good model in the future to study the impact of processing conditions and meat matrix composition on EPS production in more depth (Hilbig et al., 2019a, 2019b, 2020).…”